JP7475397B2 - Transparent liquid cosmetics - Google Patents

Description

The present invention relates to a transparent liquid cosmetic.

The stratum corneum, located in the outermost layer of the epidermis, has two functions related to moisture retention: a moisture retention function and a barrier function that controls moisture evaporation. The moisture state within the stratum corneum is determined by the balance of moisture lost through evaporation from the stratum corneum (evaporative moisture), moisture supplied to the stratum corneum from within the skin (internal moisture supply), and moisture supplied to the stratum corneum from the outside (external moisture supply).

However, in environments where the air is dry and humidity is low, such as in winter, the amount of evaporated water exceeds the amount of water supplied internally and externally, making it easy for the moisture content of the stratum corneum to decrease. Therefore, it is necessary to maintain the moisture content of the stratum corneum by improving the moisturizing function of the stratum corneum, so as to reduce the amount of evaporated water and increase the amount of water supplied externally and/or internally.

Liquid cosmetics are often used to maintain the moisture content of the stratum corneum. Liquid cosmetics containing a moisturizing component that acts to retain moisture within the stratum corneum by supplying moisture externally and/or by acquiring moisture from the external environment, and an oil-based emollient component that acts to inhibit evaporation of moisture from the stratum corneum and/or to occlude moisture in the upper part of the stratum corneum, are expected to maintain the moisture content of the stratum corneum.

Meanwhile, in Japan, the main liquid cosmetics that have moisturizing properties are transparent liquid cosmetics such as lotions and milky white liquid emulsions (creams). For example, when applied to the face, transparent liquid cosmetics are used to moisturize the skin after washing, and emulsions are used to further protect the skin with an artificial oil film after using transparent liquid cosmetics. Thus, compared to emulsions, transparent liquid cosmetics are required to have a fresh, water-like feel in the hope of moisturizing the skin. Also, clear cosmetics are preferred in the hope of providing a visual effect of freshness and moisture.

The applicant of the present application has so far marketed many liquid cosmetics. One of these is "Chifure Lotion Non-Alcohol Type," a liquid cosmetic containing sodium hyaluronate, trehalose, and di(cholesteryl/behenyl/octyldodecyl) lauroyl glutamate (see Non-Patent Document 1). In addition, there is a cosmetic described in Non-Patent Document 2 that contains sodium hyaluronate, trehalose, and di(phytosteryl/octyldodecyl) lauroyl glutamate.

Internet <URL: https://www. chifure. co. jp/products/skinlotion/2446>, retrieved April 20, 2022 Internet <https://www.cosmetic-info.jp/prod/detail.php?id=65158>, retrieved May 31, 2022

The liquid cosmetic composition described in Non-Patent Document 1 contains sodium hyaluronate and trehalose as moisturizing ingredients, and is therefore able to keep the skin fresh and moist. However, according to the inventors' investigation, the liquid cosmetic composition described in Non-Patent Document 1 has a transmittance (wavelength 660 nm) of 95.9%, and is somewhat whitish.

The cosmetic composition described in Non-Patent Document 2 has a slightly higher transmittance than the liquid cosmetic composition described in Non-Patent Document 1, but it is still only 96.7%, which is not sufficient. In addition, the cosmetic composition described in Non-Patent Document 2 has a high viscosity, is slightly stringy, and does not have a texture similar to that of water.

The problem that the present invention aims to solve is to provide a transparent liquid cosmetic that has a transmittance so high that it is close to that of water, and also has excellent moisturizing properties.

In order to solve the above problems, the inventors have investigated the moisturizing functions of moisturizing ingredients, of which there are said to be hundreds, individually and in combination. After repeated trial and error, they have found that a combination of three ingredients, sodium hyaluronate, trehalose, and di(phytosteryl/octyldodecyl) lauroyl glutamate, exhibits excellent moisturizing functions.

Surprisingly, it was found that the moisturizing effect of the combination of the above three ingredients is a synergistic effect rather than an additive effect of adding up the moisturizing effects of each ingredient when compared to the moisturizing effect of each ingredient individually. Even more surprising, the cosmetic material prepared in this way has a transmittance of 97.0% or more and can be set to a low viscosity, so that it has an appearance and feel close to water.

Based on the above findings, the inventors have succeeded in creating a transparent liquid cosmetic composition that contains sodium hyaluronate, trehalose, and di(phytosteryl/octyldodecyl) lauroyl glutamate and has a predetermined transmittance, in order to solve the problems of the present invention. The present invention has been completed based on these findings and successful examples.

Therefore, as one aspect of the present invention, there are provided cosmetics having the following embodiments.
[1] (A) sodium hyaluronate,
(B) trehalose,
(C) A transparent liquid cosmetic preparation containing di(phytosteryl/octyldodecyl) lauroyl glutamate and having a transmittance at 20°C of 97.0% or more at a wavelength of 660 nm.
[2] The transparent liquid cosmetic preparation according to [1], wherein the transparent liquid cosmetic preparation contains the components (A) to (C) such that the mass ratio ([(A)+(B)]/[(C)]) is 0.10 to 3.00.
[3] The transparent liquid cosmetic preparation according to [1], wherein the viscosity of the transparent liquid cosmetic preparation is 90 mPa·s or less when measured under conditions of 20° C., 30 rpm, and 1 minute.
[4] The transparent liquid cosmetic preparation according to any one of [1] to [3], wherein the content of the component (A) is 0.0005% by mass to 0.5% by mass, the content of the component (B) is 0.0005% by mass to 0.5% by mass, and/or the content of the component (C) is 0.01% by mass to 1.0% by mass.

The transparent liquid cosmetic composition of one embodiment of the present invention has high transmittance and excellent transparency, while also exerting a sustained moisturizing function and keeping the skin fresh and moist. Therefore, it is expected to be used daily, for example, after each face wash.

FIG. 1 shows the evaluation results of the occlusive properties of test samples 1 to 3 as described in the Examples. FIG. 2 shows the evaluation results of the water holding ability of test samples 1 and 3 as described in the Examples. FIG. 3 shows the results of evaluation of water retention of test samples 1 to 3 as described in the Examples. FIG. 4 is a graph showing the change over time in short-term stratum corneum moisture content for the test cosmetics of Example 1 and Comparative Examples 1 to 3, as described in the Examples. FIG. 5 is a graph showing the change in short-term stratum corneum moisture content 10 minutes, 70 minutes, and 120 minutes after application for the test cosmetics of Example 1 and Comparative Examples 1 to 3, as described in the Examples. FIG. 6 is a diagram showing the evaluation results of occlusive property for the test cosmetics of Examples 2 to 4, Comparative Examples 1 to 3, and Reference Examples 1 and 2, as described in the Examples. FIG. 7 is a graph showing the change over time in short-term stratum corneum moisture content for the test cosmetics of Examples 5 and 6 and purified water, as described in the Examples. FIG. 8 is a graph showing the results of measuring the long-term moisture content of the stratum corneum for the test cosmetics of Example 5 and Comparative Example 4, as described in the Examples.

The following describes in detail the cosmetic preparation, which is one aspect of the present invention, but the present invention can take various forms as long as it achieves its objectives.

Unless otherwise specified, each term in this specification is used in the sense commonly used by those skilled in the art of cosmetics and should not be interpreted as having an unduly restrictive meaning. Furthermore, the theories and speculations made in this specification are based on the inventors' knowledge and experience to date, and therefore the technical scope of the present invention is not limited solely by such theories and speculations.

"And/or" means any one or any or all combinations of two or more of the associated listed items.
"About" means an amount within ±10% of the quantity following the term. For example, "about 100" means 100 ±10%, i.e., from 90 to 110.
"Content" is synonymous with concentration and refers to the ratio of the amount of a component to the total amount of a cosmetic. However, the total amount of each component does not exceed 100%. In this specification, unless otherwise specified, the unit of content means "mass % (wt%)". When a commercially available product is used, the content of the component is preferably the amount of the component contained in the commercially available product, but may be the amount of the commercially available product itself.
"Comprising" means that elements other than the elements explicitly stated as being included can be added (same meaning as "comprising at least"), but also encompasses "consisting of" and "consisting essentially of." That is, "comprising" can mean including the elements explicitly stated and any one or more elements, consisting of the elements explicitly stated, or consisting essentially of the elements explicitly stated. Elements include limitations such as ingredients, steps, conditions, and parameters.
The number of digits in an integer value is the same as the number of significant digits. For example, 1 has one significant digit, and 10 has two significant digits. Also, the number of digits after the decimal point in a decimal value is the same as the number of significant digits. For example, 0.1 has one significant digit, and 0.10 has two significant digits.

The transparent liquid cosmetic composition of one embodiment of the present invention contains sodium hyaluronate (hereinafter also referred to as component (A)), trehalose (hereinafter also referred to as component (B)), and di(phytosteryl/octyldodecyl) lauroyl glutamate (hereinafter also referred to as component (C)). Furthermore, the transparent liquid cosmetic composition of one embodiment of the present invention is characterized in that, while containing these components (A) to (C), it has a transmittance of 97.0% or more at a wavelength of 660 nm at 20°C.

Sodium hyaluronate, which is component (A), is a type of water-soluble mucopolysaccharide and is used in cosmetics as a moisturizer. The molecular weight of sodium hyaluronate may affect the viscosity of the cosmetic. That is, cosmetics containing sodium hyaluronate with a large molecular weight tend to have high occlusiveness and remain on the skin surface, but tend to have high viscosity. Therefore, the upper limit of the molecular weight (GPC) of sodium hyaluronate is preferably about 3 million daltons, more preferably 2 million daltons. The lower limit of the molecular weight (GPC) of sodium hyaluronate is typically 5,000 daltons. The molecular weight of sodium hyaluronate can be appropriately set depending on the viscosity imparted to the transparent liquid cosmetic of one embodiment of the present invention, the content of sodium hyaluronate, and the like.

There are no particular limitations on the method for obtaining sodium hyaluronate, and examples of such methods include extraction and purification from animal tissues such as cockscomb, skin, and cartilage tissue using conventional methods, obtaining it through microbial fermentation, and purchasing it as a commercially available product. Examples of commercially available sodium hyaluronate include the grades "HMW", "MMW", "LMW" and "VLMW" of the "BIO-SODIUM HYALURONATE POWDER" series (all manufactured by HYUNDAI BIOLAND), hyaluronic acid "FCH-200", "FCH-150", "FCH-120", "FCH-80", "FCH-60" and "FCH-SU" (manufactured by Kikkoman Biochemifa Corporation), "Hyaluronic Acid HA-LQ", "Hyaluronic Acid HA-LQH", "HAbooster (registered trademark)" (manufactured by Kewpie Corporation), "PrimalHyaltm (registered trademark) Ultrafiller" and "Sodium hyaluronate powder" (manufactured by Horus Co., Ltd.). Sodium hyaluronate may be hydrolyzed sodium hyaluronate or sodium hyaluronate in which some of the substituents have been acetylated. The sodium hyaluronate may be used alone or in combination of two or more of the above.

Trehalose, component (B), is a disaccharide formed by 1,1-glycosidic bonds between glucose. There are no particular limitations on the method for obtaining trehalose, and examples of such methods include obtaining it by yeast fermentation, obtaining it from plant materials such as starch, chemical synthesis, and purchasing it as a commercially available product. An example of a commercially available trehalose product is "Trehalose (for cosmetics)" (manufactured by Hayashibara Co., Ltd.).

Component (C), di-(phytosteryl/octyldodecyl) lauroyl glutamate, is an amino acid-based oil agent consisting of L-glutamic acid, lauric acid, higher alcohol, and phytosterol. There are no particular limitations on the method for obtaining di-(phytosteryl/octyldodecyl) lauroyl glutamate, and examples of such methods include chemical synthesis and purchasing a commercially available product. Commercially available products of di-(phytosteryl/octyldodecyl) lauroyl glutamate include, for example, "ELDEW (registered trademark) PS-203" (manufactured by Ajinomoto Co., Inc.) and "Plandool (registered trademark)-LG2" (manufactured by Nippon Fine Chemicals Co., Ltd.).

The transparent liquid cosmetic composition of one embodiment of the present invention is able to exert a sustained moisturizing function by containing components (A) to (C). Furthermore, the transparent liquid cosmetic composition of one embodiment of the present invention is able to exhibit superior occlusive properties by having the contents of components (A) to (C) in a specific relationship. From this viewpoint, the transparent liquid cosmetic composition of one embodiment of the present invention preferably contains components (A) to (C) such that the mass ratio ([(A)+(B)]/[(C)]) is 0.10 to 3.00, more preferably 0.20 to 2.60, and even more preferably 0.30 to 1.75.

The contents of components (A), (B) and (C) are preferably adjusted to the above-mentioned mass ratio. For example, taking into consideration the transparency, viscosity, stability and the like of the transparent liquid cosmetic of one embodiment of the present invention, the content of component (A) is preferably 0.0005% to 0.5% by mass, more preferably 0.001% to 0.5% by mass, and even more preferably 0.01% to 0.1% by mass; the content of component (B) is preferably 0.0005% to 0.5% by mass, more preferably 0.001% to 0.5% by mass, and even more preferably 0.01% to 0.3% by mass; and the content of component (C) is preferably 0.01% to 1.0% by mass, more preferably 0.02% to 0.8% by mass, and even more preferably 0.03% to 0.6% by mass.

The transparent liquid cosmetic composition of one embodiment of the present invention has excellent transparency while containing components (A) to (C). The transparency of the transparent liquid cosmetic composition of one embodiment of the present invention may be such that the transmittance at a wavelength of 660 nm at 20°C is 97.0% or more, but in order to achieve even greater transparency, the transmittance is preferably 98.0% or more, and more preferably 99.0% or more. The transparent liquid cosmetic composition of one embodiment of the present invention may be colored by the components contained therein, but is preferably colorless or pale white.

The transparent liquid cosmetic composition of one embodiment of the present invention preferably has a low viscosity so as to have a water-like feel. In such a case, the transparent liquid cosmetic composition of one embodiment of the present invention preferably has a viscosity of 90 mPa·s or less, more preferably 50 mPa·s or less, even more preferably 20 mPa·s or less, and even more preferably 10 mPa·s or less or 5.0 mPa·s or less, measured under measurement conditions of 20°C, 30 rpm, and 1 minute. The lower limit of the viscosity is typically 0.1 mPa·s.

The transmittance and viscosity of the transparent liquid cosmetic of one embodiment of the present invention are values obtained by measuring using the method described in the Examples below.

The transparent liquid cosmetic composition of one embodiment of the present invention may contain other ingredients in addition to the ingredients (A) to (C), so long as it has excellent transparency and exhibits excellent moisturizing properties.

The other components are not particularly limited, and examples include components used in ordinary liquid cosmetics, more specifically water, oils, moisturizers, preservatives, pH adjusters, emulsifiers, antioxidants, cooling agents, chelating agents, cosmetic ingredients, various other medicinal ingredients, powders, fragrances, coloring materials, etc. The content of the other components can be appropriately set by a person skilled in the art as long as it does not interfere with the solution of the problems of the present invention. Some of the other components are listed below, but these are merely examples and are not limiting.

The water may be any water used in the production of cosmetics, such as purified water, ion-exchanged water, and tap water. The water content is preferably 70% to 90% by mass, and more preferably 80% to 90% by mass.

Examples of oils include oil-based emollient components, specifically triethylhexanoin, isononyl isononanoate, isotridecyl isononanoate, diisostearyl malate, ethylhexyl palmitate, cetyl ethylhexanoate, dipentaerythrityl hexahydroxystearate, pentaerythrityl tetraisostearate, dimer dilinoleyl bis(behenyl/isostearyl/phytosteryl) dimer dilinoleate, stearyl alcohol, cetearyl alcohol, etc. Examples of the oils include choline, behenyl alcohol, dimethicone, cyclopentasiloxane, methylphenyl polysiloxane, diphenylsiloxyphenyl trimethicone, squalane, mineral oil, hydrogenated poly(C6-12 olefin), ethylhexyl methoxycinnamate, polyglyceryl-2 triisostearate, olive fruit oil, jojoba seed oil, lavender oil, evening primrose oil, avocado oil, camellia seed oil, and macadamia seed oil. These oils may be used alone or in combination of two or more. The content of the oil is preferably 0% to 1.5% by mass, and more preferably 0% to 0.6% by mass.

Examples of moisturizing agents include glycerin, butylene glycol (BG), propylene glycol (PG), diglycerin, dipropylene glycol (DPG), methyl gluceth-10, methyl gluceth-20, PEG/PPG/polybutylene glycol-8/5/3 glycerin, xylitol, maltitol, maltose, sorbitol, inositol, erythritol, glucose, fructose, hydrolyzed elastin, sodium lactate, cyclodextrin, pyrrolidone carboxylic acid, and urea. These may be used alone or in combination of two or more. The content of the moisturizing agent is preferably 0% to 30% by mass, but in order to impart a superior moisturizing function to the transparent liquid cosmetic composition of one embodiment of the present invention, it is more preferable that the content is 5% to 25% by mass, and even more preferable that the content is 10% to 20% by mass.

Examples of preservatives include paraoxybenzoic acid esters (methylparaben, propylparaben, etc.) and their sodium salts, phenoxyethanol, benzoic acid, benzoates, salicylic acid, salicylates, sorbic acid and its salts, chlorphenesin, hinokitiol, isopropylmethylphenol, parachlorophenol, benzalkonium chloride, chlorhexidine hydrochloride, trichlorocarbanilide, photosensitizers, etc., and these can be used alone or in combination of two or more. The content of the preservative is preferably 0% to 1% by mass.

Examples of pH adjusters include lactic acid, citric acid, sodium citrate, glycolic acid, succinic acid, tartaric acid, malic acid, sodium malate, etidronic acid, potassium carbonate, sodium bicarbonate, ammonium bicarbonate, sodium hydroxide, potassium hydroxide, arginine, triethanolamine, and monoethanolamine. These can be used alone or in combination of two or more. The content of the pH adjuster is preferably 0% to 1% by mass. The pH adjuster is also called a neutralizing agent.

Examples of emulsifiers include lipophilic emulsifiers and hydrophilic emulsifiers. Specific examples of emulsifiers include glycerin fatty acid esters such as glyceryl stearate (SE); polyglycerin fatty acid esters such as polyglyceryl-6 laurate, polyglyceryl-10 myristate, polyglyceryl-10 stearate, and polyglyceryl-10 isostearate; PEG-5 glyceryl stearate, PEG-15 glyceryl stearate, PEG-15 glyceryl isostearate, PEG-20 glyceryl triisostearate, and PEG-10 oleate. sorbitan fatty acid esters such as sorbitan coconutate, sorbitan oleate, sorbitan sesquioleate, and sorbitan palmitate; polyoxyethylene sorbitan fatty acid esters such as polysorbate 40, polysorbate 60, polysorbate 80, and PEG-20 sorbitan isostearate; polyoxyethylene sorbitan fatty acid esters such as sorbeth-6 laurate, sorbeth-6 tetraoleate, sorbeth-30 tetraoleate, and sorbeth-60 tetraoleate; fatty acid esters; polyoxyethylene hydrogenated castor oils such as PEG-20 hydrogenated castor oil, PEG-30 hydrogenated castor oil, PEG-60 hydrogenated castor oil, and PEG-50 hydrogenated castor oil triisostearate; polyoxyethylene alkyl ethers such as polyoxyethylene cetyl ether (ceteth-20), polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, and polyoxyethylene behenyl ether; PPG-4 ceteth-1, PPG-8 ceteth-20, PPG-6 decyltetradeceth-12, and PPG-6 decyltetradeceth-20; Examples of the emulsifier include polyoxyethylene polyoxypropylene alkyl ethers such as Ladeceth-20; polyethylene glycol fatty acid esters such as PEG-10 laurate, PEG-10 stearate, PEG-25 stearate, PEG-40 stearate, PEG-45 stearate, PEG-55 stearate, PEG-10 oleate, PEG-150 distearate, and PEG-8 diisostearate; and lecithin derivatives such as hydrogenated lecithin and hydrogenated lysolecithin. These may be used alone or in combination of two or more. The content of the emulsifier is preferably 0% by mass to 5% by mass.

Examples of antioxidants include vitamin E and its derivatives, such as dibutylhydroxytoluene (BHT), butylhydroxyanisole (BHA), and tocopherol; thiotaurine, evening primrose extract, β-carotene, catechin compounds, flavonoid compounds, polyphenol compounds, and sodium pyrosulfite; these can be used alone or in combination of two or more. The content of the antioxidant is preferably 0% to 1% by mass.

Examples of chelating agents include alanine, disodium edetate (EDTA-2Na), sodium polyphosphate, sodium metaphosphate, sodium phytate, trisodium phosphate, and sodium gluconate. These can be used alone or in combination of two or more. The content of the chelating agent is preferably about 0% to 0.1% by mass.

Examples of beauty ingredients include apple tannin (apple fruit extract), licorice root extract, resveratrol, tuberose polysaccharide, isomerized sugar, Japanese laurel juice, chinpi extract, and dipotassium glycyrrhizinate. These can be used alone or in combination of two or more. The content of the beauty ingredient is preferably 0% to 5% by mass.

Examples of medicinal ingredients include ascorbic acid and its salts and derivatives, allantoin, nicotinamide, hydroquinone and its glycosides, tranexamic acid, kojic acid, and those listed in the "List of Active Ingredients in Medicinal Cosmetics." These can be used alone or in combination of two or more. The content of the medicinal ingredient is preferably 0% to 5% by mass.

The function and/or effect of the transparent liquid cosmetic composition of one embodiment of the present invention is not particularly limited, so long as it is used as a cosmetic composition. The transparent liquid cosmetic composition of one embodiment of the present invention exhibits excellent moisturizing function. The moisturizing function of the transparent liquid cosmetic composition of one embodiment of the present invention can be evaluated, for example, by the occlusive property, water holding ability, water retention ability, and stratum corneum moisture content described in the Examples below.

The transparent liquid cosmetic preparation according to one embodiment of the present invention has superior occlusive properties and/or stratum corneum moisture content compared to a transparent liquid cosmetic preparation that contains component (A) and component (B) but does not contain component (C) and that has substantially similar other ingredients, or compared to a transparent liquid cosmetic preparation that contains component (C) but does not contain components (A) and (B) and that has substantially similar other ingredients.

The method for producing the transparent liquid cosmetic of one embodiment of the present invention is not particularly limited, and it can be produced by mixing a water-soluble component with water to form an aqueous phase, mixing a lipophilic component to form an oil phase, and then gradually adding the oil phase while stirring the aqueous phase, and mixing until the entire mixture is homogeneous. In these steps, heating may be performed as appropriate. The temperature during heating is not particularly limited, but is, for example, 65°C to 85°C.

The transparent liquid cosmetic composition of one embodiment of the present invention is not particularly limited in its mode of use or formulation, and can be used, for example, in skin care cosmetics such as lotions and serums. The transparent liquid cosmetic composition of one embodiment of the present invention can be impregnated into sheets or sprayed. It is therefore expected that the transparent liquid cosmetic composition of one embodiment of the present invention will be in the form of an impregnated sheet, an impregnated mask, or a spray pump.

The transparent liquid cosmetic of one embodiment of the present invention has a water-like feel, but when applied to the skin, it increases the moisture content of the stratum corneum and/or inhibits evaporation of moisture from the skin, exerting a sustained and excellent moisturizing function and keeping the skin fresh and moist.

The present invention will be explained in more detail below with reference to examples, but the present invention is not limited to these examples, and the present invention can take various forms as long as the problem of the present invention can be solved.

Example 1: Evaluation of moisturizing properties of three ingredients
[1-1 Preparation of test sample]
As the di(phytosteryl/octyldodecyl) lauroyl glutamate, "ELDEW (registered trademark) PS-203" (manufactured by Ajinomoto Co., Ltd.) was used. As the sodium hyaluronate, "BIO-SODIUM HYALURONATE POWDER (MMW)" (manufactured by HYUNDAI BIOLAND Co., Ltd.) (molecular weight: 1.5 MDa (GPC)) was used. As the trehalose, "Trehalose (for cosmetics)" (manufactured by Hayashibara Co., Ltd.) was used.

Di(phytosteryl/octyldodecyl) lauroyl glutamate alone was used as test sample 1. An aqueous solution of 2% by mass sodium hyaluronate and 20% by mass trehalose was used as test sample 2.

A mixture of commercially available di(phytosteryl/octyldodecyl) lauroyl glutamate, sodium hyaluronate, and trehalose in a mass ratio of 10:1:3 was used as test sample 3.

[1-2 Evaluation Method]
(1-2-1) Occlusivity A filter paper with 50 mg of test sample evenly applied was placed on the mouth of a standard bottle (PS-7K) containing 15 g of purified water and allowed to stand at room temperature. With the filter paper removed, the weight of the bottle was measured before the test and after 24 hours had passed. As a control, a filter paper without the test sample applied was used and similarly measured. The transpiration inhibition rate of each test sample was calculated using the following formula to evaluate occlusion (repeated 3 times).
Evaporation inhibition rate (%) of test sample = [T ₀ - T ₂₄ ]/[t ₀ - t ₂₄ ] x 100
T ₀ : Weight of the bottle before the test when the test sample was used T ₂₄ : Weight of the bottle after 24 hours when the test sample was used t ₀ : Weight of the bottle before the test when the control was used t ₂₄ : Weight of the bottle after 24 hours when the control was used

(1-2-2) Water Holding Capacity For test samples 1 and 3, 10 g of the test sample was weighed out into a mortar, and 0.4 g of purified water was added dropwise while stirring manually with a pestle to thoroughly mix the test sample and purified water. After uniform mixing, 0.4 g of purified water was added dropwise and stirred and mixed in the same manner. This was repeated until the test sample and purified water could no longer be mixed and the water was visually separated, which was the end point. The water holding capacity was evaluated by calculating the water holding capacity according to the following formula (repeated 3 times).
Water holding rate (%) = [total amount of purified water dropped before the end point] / [amount of test sample] × 100

(1-2-3) Water Retention Capacity For test samples 1 and 3, a mixture of the test sample and purified water at the end point (maximum water retention state) obtained when testing water retention capacity was used as a sample. For test sample 2, it was used as a sample by itself.

After thoroughly mixing the sample again, 2 g was weighed into a standard bottle (PS-7K) and left uncapped in a desiccator containing silica gel for 24 hours. The weight of the bottle was measured before and after 24 hours had passed, and the water retention rate (moisture change rate) was calculated by expressing the weight of the bottle after 24 hours as a percentage of the weight of the bottle before the test, and the water retention was evaluated.

[1-3 Evaluation results]
The test samples 1 to 3 were evaluated for occlusion property, water holding property and water retention property, and the results are shown in FIGS.

As shown in Figure 1, Test Sample 3 contained less di(phytosteryl/octyldodecyl) lauroyl glutamate than Test Sample 1, and further contained sodium hyaluronate and trehalose, which did not show occlusive properties, yet had the same level of occlusive properties as Test Sample 1. Furthermore, Test Sample 3 had better water holding ability than Test Sample 1. There was also no significant difference in water retention between Test Sample 3 and Test Sample 1.

These results show that the combination of the three ingredients di(phytosteryl/octyldodecyl) lauroyl glutamate, sodium hyaluronate, and trehalose exerts a synergistic effect in terms of occlusion, water holding, and water retention.

Since dilauroyl glutamate (phytosteryl/octyldodecyl) is an oil, it is difficult to dissolve in water, and when mixed with water, it is added slowly while stirring. However, if water-soluble sodium hyaluronate and trehalose are used in addition to dilauroyl glutamate (phytosteryl/octyldodecyl), the content of dilauroyl glutamate (phytosteryl/octyldodecyl) can be reduced while imparting the same or greater occlusiveness, water-holding property, and water-retentive property to the cosmetic, this has the advantage that dilauroyl glutamate (phytosteryl/octyldodecyl) can be easily solubilized in the manufacturing process of aqueous cosmetics, reducing concerns about separation and improving the manufacturing efficiency of the cosmetic.

Example 2: Evaluation of short-term moisturizing properties of transparent liquid cosmetics (1)
[2-1 Preparation of test cosmetics]
Various test cosmetics were prepared as transparent liquid cosmetics by the following procedure according to the formulations shown in Table 1. Note that the numerical values "%" in the table indicate mass % (wt %).

A mixture of sodium hyaluronate, trehalose, methylparaben and water (aqueous phase) was heated to 75°C so that methylparaben was uniformly dissolved. A uniform mixture of di(phytosteryl/octyldodecyl) lauroyl glutamate and PPG-8 ceteth-20 (oil phase) was heated to 75°C to eliminate the temperature difference with the aqueous phase. The aqueous phase was gently stirred (180 rpm) with a paddle while the oil phase was added and mixed uniformly. The mixture was gradually cooled to 30°C while continuing to stir, to obtain the test cosmetic of Example 1. The test cosmetics of Comparative Examples 1 to 3 were prepared in the same manner, but without sodium hyaluronate, trehalose and/or di(phytosteryl/octyldodecyl) lauroyl glutamate.

[2-2 Evaluation Method]
(2-2-1) Moisture content of the stratum corneum (short term)
Twelve randomly selected panelists were allowed to acclimate (standby) for 20 minutes in a skin measurement room set at a temperature of 22°C and humidity of 50%, and then the test cosmetics (Example 1, Comparative Examples 1 to 3) were directly applied to the skin of the inner forearm at an application amount of 1 mg/ ^cm2 . For each application site, the stratum corneum moisture content was measured before application and every 10 minutes after application for 2 hours using a skin measuring device "Corneometer CM825" (manufactured by COURAGE-KHAZAKA electronic GmbH). Measurements were made at four locations for each application site of the test cosmetics. The difference between the stratum corneum moisture content before application (0 minutes: no application) and the stratum corneum moisture content after a certain time period was calculated as the change (ΔAU). Statistical analysis was performed using a paired t-test on the measurement results at the plateau (the time when the degree of decrease in the measured value settled after application).

[2-3 Evaluation Results]
(2-3-1) Moisture content of the stratum corneum (short term)
FIG. 4 is a graph showing the change in short-term stratum corneum moisture content over time for the test cosmetics of Example 1 and Comparative Examples 1 to 3, and FIG. 5 is a graph showing the change in short-term stratum corneum moisture content 10 minutes, 70 minutes, and 120 minutes after application.

As shown in Figures 4 and 5, the test cosmetic of Example 1 had a higher stratum corneum moisture content at all times compared to the test cosmetics of Comparative Examples 1 to 3. Furthermore, for the test cosmetic of Example 1, almost no difference was observed between 70 and 120 minutes after application. This was also the case for the test cosmetic of Comparative Example 2 (containing only Eldew). However, for the test cosmetic of Comparative Example 3 (containing sodium hyaluronate and trehalose), the stratum corneum moisture content 120 minutes after application was lower than the stratum corneum moisture content 70 minutes after application.

Although the test cosmetic of Example 1 contained sodium hyaluronate and trehalose, there was almost no difference in the moisture content of the stratum corneum 70 minutes and 120 minutes after application. This result indicates that the moisture retention effect of the combination of the three ingredients di(phytosteryl/octyldodecyl) lauroyl glutamate, sodium hyaluronate, and trehalose on the stratum corneum is a synergistic effect rather than an additive effect of each ingredient.

In addition, when the test cosmetics of Comparative Example 2 and Comparative Example 3 were compared, the test cosmetic of Comparative Example 3 had a higher stratum corneum moisture content 10 minutes after application, and the test cosmetic of Comparative Example 2 had a higher stratum corneum moisture content 70 minutes after application. From these results, it was found that in a relatively short period after application, the water holding capacity of sodium hyaluronate and trehalose exceeded the water holding capacity and occlusive capacity of di(phytosteryl/octyldodecyl) lauroyl glutamate, and the moisturizing function of sodium hyaluronate and trehalose was exerted. It was also found that as time passed after application, the decrease in stratum corneum moisture content was suppressed more by the occlusive capacity of di(phytosteryl/octyldodecyl) lauroyl glutamate than by the water holding capacity of sodium hyaluronate and trehalose. It is believed that the combination of these three ingredients synergistically exerts the water-holding properties of sodium hyaluronate and trehalose, and the water-holding and occlusive properties of di(phytosteryl/octyldodecyl) lauroyl glutamate, helping to maintain moisture in the stratum corneum for a long period of time.

Example 3: Evaluation of Occlusion Properties of Transparent Liquid Cosmetics
[3-1 Preparation of test cosmetics]
Various test cosmetics were prepared as transparent liquid cosmetics in the same manner as in 2-1 above, according to the formulations shown in Table 2. The numerical values "%" in the table indicate mass % (wt %).

[3-2 Evaluation Method]
(3-2-1) Occlusivity The occlusion property was evaluated in the same manner as in 1-2-1 above (repeated 3 times). However, in order to make it easier to compare the transpiration inhibition ratios of the test cosmetic preparations obtained in Comparative Example 1 with the other test cosmetic preparations, the transpiration inhibition ratios of the test cosmetic preparations were calculated by subtracting the transpiration inhibition ratio of Comparative Example 1 from the transpiration inhibition ratio of each test cosmetic preparation.

[3-3 Evaluation Results]
(3-3-1) Occlusion Property The evaluation results of occlusion property for the test cosmetics of Examples 2 to 4, Comparative Examples 1 to 3, and Reference Examples 1 and 2 are shown in Fig. 6. The ratio of the three components indicates [total content of sodium hyaluronate and trehalose]/[content of di(phytosteryl/octyldodecyl) lauroyl glutamate].

From the results in Figures 1 to 3, it was assumed that the higher the content of the oil di(phytosteryl/octyldodecyl) lauroyl glutamate (the smaller the three-component ratio), the higher the occlusiveness. However, in reality, as shown in Figure 6, when the results of Reference Example 1, Examples 2 to 4, and Reference Example 2 are arranged in order of the three-component ratio, it was found that the results show a normal distribution with Example 3 (three-component ratio 1.00) as the maximum value.

These results show that by combining di(phytosteryl/octyldodecyl) lauroyl glutamate with sodium hyaluronate and trehalose in a specific ratio, occlusiveness (moisture evaporation inhibition effect) is improved.

Example 4: Evaluation of short-term moisturizing properties of transparent liquid cosmetic preparations (2)
[4-1 Preparation of test cosmetics]
Various test cosmetics were prepared as transparent liquid cosmetics by the following procedure according to the formulations shown in Table 3. Note that the numerical values "%" in the table indicate mass % (wt %).

A homogeneous mixture of ingredients (1), (2), (4) to (7), (13), (14), and (16) (aqueous phase) was heated to 75°C so that methylparaben was uniformly dissolved. A homogeneous mixture of ingredients (3), (8) to (12), and (15) (oil phase) was heated to 75°C to eliminate the temperature difference with the aqueous phase. While gently stirring the aqueous phase with a paddle (rotation speed 180 rpm), the oil phase was added and mixed until homogeneous. Each test cosmetic was obtained by gradually cooling to 30°C while continuing to stir.

[4-2 Evaluation Method]
(4-2-1) Moisture content of the stratum corneum (short term)
Seven randomly selected panelists were asked to determine the change in stratum corneum moisture content (ΔAU) using the test cosmetics (Examples 5-6) and water (purified water) in the same manner as in 2-2-1 above.

[4-3 Evaluation Results]
(4-3-1) Moisture content of the stratum corneum (short term)
FIG. 7 is a graph showing the change over time in short-term stratum corneum moisture content for the test cosmetics of Examples 5 and 6 and purified water.

As shown in Figure 7, the test cosmetics of Examples 5 and 6 were found to have the same moisture-retaining effect on the stratum corneum as the test cosmetic of Example 1 shown in Figure 4.

Example 5: Evaluation of long-term moisturizing properties of transparent liquid cosmetic materials
[5-1 Evaluation Method]
(5-1-1) Moisture content of the stratum corneum (long-term)
Twenty-one randomly selected panelists (women in their 30s to 50s) were asked to apply the test cosmetic of Example 5 to one half of their face twice a day for two weeks, and the test cosmetic of Comparative Example 4 to the other half of their face. The panelists were not informed of which cosmetic was used (blind test). The moisture content of the stratum corneum was measured on both cheeks before and two weeks after application in the same manner as in 2-2-1 above. The relative value of the moisture content of the stratum corneum two weeks after application of each test cosmetic was calculated, assuming that the moisture content of the stratum corneum before application was 100%.

[5-2 Evaluation Results]
(5-2-1) Moisture content of the stratum corneum (long-term)
The results of measuring the moisture content of the stratum corneum (long term) for the test cosmetics of Example 5 and Comparative Example 4 are shown in FIG.

As shown in Figure 8, the relative value for the test cosmetic of Example 5 was approximately 102%, which was greater than that of the test cosmetic of Comparative Example 4, which showed almost no change. This demonstrates that the cosmetic containing the three components di(phytosteryl/octyldodecyl) lauroyl glutamate, sodium hyaluronate, and trehalose exhibits excellent moisturizing function even when applied continuously for two weeks. The test cosmetic of Example 5 maintained its moisture retention effect in the stratum corneum even four weeks after application.

Example 6: Evaluation of transmittance and viscosity of transparent liquid cosmetic preparations
[6-1 Evaluation Method]
(6-1-1) Transmittance According to "General Test Method 2.61 Turbidity Test Method" of the 18th Edition of the Japanese Pharmacopoeia, the transmittance of the test cosmetic at a wavelength of 660 nm was measured (repeated three times) at 20°C using an ultraviolet-visible spectrophotometer ("UV-1900"; manufactured by Shimadzu Corporation). The cell used was "ASLAB Standard Quartz Cell Q-244" (manufactured by AS ONE Corporation).

(6-1-2) Viscosity A Brookfield viscometer ("VISCOMETER TVB-25L" manufactured by Toki Sangyo Co., Ltd.) and a rotor ("L/Adp" manufactured by Toki Sangyo Co., Ltd.) were used. The measurement conditions were 30 rpm, 1 minute for the test cosmetic material at 20°C.

[6-2 Evaluation Results]
The transmittance and viscosity were measured for the test cosmetics of Examples 5 and 6, the test cosmetic of Reference Example 3 ("Chifure Non-alcoholic Lotion" described in Non-Patent Document 1), and the test cosmetic of Reference Example 4 ("Dr. Ci:Labo VC100 Essence Lotion EX Special" described in Non-Patent Document 2), and the results are shown in Table 4.

As shown in Table 4, the test cosmetics of Examples 5 to 6 had a transmittance of 99% or more and were colorless, clear liquids. In contrast, the test cosmetics of Reference Examples 3 and 4 had a transmittance of 97% or less. Furthermore, when the test cosmetics of Examples 5 to 6 were statistically analyzed against the test cosmetic of Reference Example 4 using an unpaired t-test, the results were all p<0.001, indicating a significant difference.

As for viscosity, as shown in Table 4, the test cosmetics of Examples 5-6 and Reference Example 3 had a viscosity of 5 mPa·s or less. In contrast, the test cosmetic of Reference Example 4 had a viscosity of approximately 100 mPa·s, which felt relatively viscous. The test cosmetic of Reference Example 4 had a viscosity value that varied depending on the rotation speed, and was considered to be a non-Newtonian fluid.

These results show that the test cosmetics of Examples 5 and 6 are clear because they have a transmittance of 99% or more, and because they have a viscosity of 5 mPa·s or less, they are transparent liquid cosmetics that feel similar to water.

In addition, the results of Examples 1 to 6 show that a transparent liquid cosmetic containing three components, di(phytosteryl/octyldodecyl) lauroyl glutamate, sodium hyaluronate, and trehalose, in a specified ratio is clear and feels similar to water, while also exhibiting excellent moisturizing properties.

The test cosmetics of Examples 7 to 9 shown in Tables 5 to 7 were produced in the same manner as the test cosmetics of Examples 5 to 6. The test cosmetics of Examples 7 to 9 had the same transmittance and viscosity as the test cosmetics of Examples 5 to 6.

The transparent liquid cosmetic composition of one embodiment of the present invention exerts synergistic occlusiveness, water-holding and water-retentive properties due to the three components of di(phytosteryl/octyldodecyl) lauroyl glutamate, sodium hyaluronate and trehalose, and while it has an excellent moisturizing effect, it can also exhibit transparency and a feel similar to that of water, and therefore can be used as skin care cosmetics such as lotions, impregnated sheets, impregnated masks and sprays. By using the transparent liquid cosmetic composition of one embodiment of the present invention, users can expect to reduce or prevent dry skin in a comfortable manner on a daily basis.

Claims (3)

(A) sodium hyaluronate,
(B) trehalose,
(C) di(phytosteryl/octyldodecyl) lauroyl glutamate, and a transparent liquid cosmetic preparation having a transmittance at 20°C of 97.0% or more at a wavelength of 660 nm ,
The content of the component (C) is 0.01% by mass to 0.6% by mass, and
The transparent liquid cosmetic preparation comprises the components (A) to (C) such that the mass ratio ([(A)+(B)]/[(C)]) is 0.10 to 3.00. The transparent liquid cosmetic according to claim 1, wherein the viscosity of the transparent liquid cosmetic is 90 mPa·s or less when measured under conditions of 20°C, 30 rpm, and 1 minute. The transparent liquid cosmetic preparation according to any one of claims 1 to 2, wherein the content of the component (A) in the transparent liquid cosmetic preparation is 0.0005% by mass to 0.5% by mass, and/or the content of the component (B) in the transparent liquid cosmetic preparation is 0.0005% by mass to 0.5 % by mass.